<!DOCTYPE html>
<html>
<head>
    <title>Chat App</title>
    <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css">
</head>
<body>
    <nav class="navbar navbar-expand-lg navbar-light bg-light">
        <div class="container">
            <a class="navbar-brand" href="/">Chat App</a>
            <div class="navbar-nav">
                {% if user.is_authenticated %}
                    <a class="nav-item nav-link" href="{% url 'logout' %}">Logout</a>
                {% else %}
                    <a class="nav-item nav-link" href="{% url 'login' %}">Login</a>
                    <a class="nav-item nav-link" href="{% url 'register' %}">Register</a>
                {% endif %}
            </div>
        </div>
    </nav>
    <div class="container mt-4">
        {% block content %}{% endblock %}
    </div>
</body>
</html>